Improve messages and behaviour when detecting unhappy installation paths

- in case of major version mismatch, raise immediately an error
- in case of a mix between conda and something else (pip or a cloned source folder), we suggest deactivating the conda env or install the library inside this later
- discourage using system-wide khiops binary and a library inside a conda env

Author: Thierry RAMORASOAVINA

khiops/core/internals/runner.py

@@ -1076,12 +1076,31 @@ def _initialize_khiops_version(self):
             error_msg += f"\nstderr: {stderr}" if stderr else ""
             raise KhiopsRuntimeError(error_msg)
 
+        # Khiops core version
         self._khiops_version = KhiopsVersion(khiops_version_str)
 
-        # Warn if the khiops version does not match the Khiops Python library version
-        # Note: Currently the check is very strict. It may be loosened in the future
-        # (major.minor.patch must be the same)
+        # Library version
         compatible_khiops_version = khiops.get_compatible_khiops_version()
+
+        operating_system = platform.system()
+        installation_method = _infer_khiops_installation_method()
+
+        # Fail immediately if the major versions differ
+        # Note: the installation status will not show at all
+        if self.khiops_version.major != compatible_khiops_version.major:
+            raise KhiopsRuntimeError(
+                f"Major version '{self.khiops_version.major}' of the Khiops "
+                "executables does not match the Khiops Python library major version "
+                f"'{compatible_khiops_version.major}'. "
+                "To avoid any compatibility error, "
+                "please update either the Khiops "
+                f"executables package for your '{operating_system}' operating "
+                "system, or the Khiops Python library, "
+                f"according to your '{installation_method}' environment. "
+                "See https://khiops.org for more information.",
+            )
+
+        # Warn if the khiops version does not match the Khiops Python library version
         # KhiopsVersion implements the equality operator, which however also
         # takes pre-release tags into account.
         # The restriction here does not apply to pre-release tags
@@ -1094,8 +1113,6 @@ def _initialize_khiops_version(self):
             compatible_khiops_version.minor,
             compatible_khiops_version.patch,
         ):
-            operating_system = platform.system()
-            installation_method = _infer_khiops_installation_method()
             warnings.warn(
                 f"Version '{self._khiops_version}' of the Khiops executables "
                 "does not match the Khiops Python library version "
@@ -1160,8 +1177,9 @@ def _detect_library_installation_incompatibilities(self, library_root_dir):
                     f"Khiops Python library installation path '{library_root_dir}' "
                     "does not match the current Conda environment "
                     f"'{os.environ['CONDA_PREFIX']}'. "
-                    "Please install the Khiops Python library "
-                    "in the current Conda environment. "
+                    "Either deactivate the current Conda environment "
+                    "or use the Khiops Python library "
+                    "belonging to the current Conda environment. "
                     "Go to https://khiops.org for instructions.\n"
                 )
                 error_list.append(error)
@@ -1172,7 +1190,7 @@ def _detect_library_installation_incompatibilities(self, library_root_dir):
                     f"Khiops binary path '{self.khiops_path}' "
                     "does not match the current Conda environment "
                     f"'{os.environ['CONDA_PREFIX']}'. "
-                    "Please install the Khiops binary "
+                    "We recommend installing the Khiops binary "
                     "in the current Conda environment. "
                     "Go to https://khiops.org for instructions.\n"
                 )